Discussions regarding pitchers usually center on starters and closers. Rarely do middle relievers get the attention they deserve. Royals left-hander Donnie Joseph made me sit up in my seat and take notice.

Currently serving as a mid-to-late-game reliever, Joseph has outstanding upside. Scouting him during Spring Training, I saw he had enough stuff to eventually close games.

Joseph, 25, is physically fit, tall and slender at 6-foot-3 and 190 pounds. He was a basketball, football and baseball star at Hays High School in Buda, Texas. As a junior, Joseph had an 8-1 record with a 1.40 ERA. He was a member of the National Honor Society, a tribute to his scholarship and citizenship.

Joseph went to the University of Houston, where he served as a starter and then found himself closing for the Cougars, saving 11 games his junior year. He struck out 75 and posted a 2.16 ERA in 50 innings. The Reds selected Joseph in the third round of the 2009 First-Year Player Draft.

This past July, Joseph was traded from Cincinnati to Kansas City along with right-hander J.C. Sulbaran for veteran right-handed reliever Jonathan Broxton. The trade is one that could prove to be very beneficial for both clubs.

At the time of the trade, many scouts and analysts felt the hard-throwing Sulbaran was the major component in the deal for Kansas City. Clearly, Joseph may be equally -- if not more -- important to the Royals' future.

Joseph throws two very nasty pitches. I saw him throw high-80s to low-90s two-seam fastballs with good movement. The fastballs set up a very efficient and effective slider. It's the type of biting slider that he can use as his out pitch. Joseph isn't afraid to double up on either pitch and throw them back to back in any count.

I found Joseph to be extremely tough against left-handed hitters, and one might think he is best suited as a left-handed specialist. That could be true. I think he's more than that. I think Joseph will give all hitters fits. At about 10 mph slower than his fastball and with tremendous movement, his wicked slider is a very difficult pitch to hit.

So far this spring, Joseph has shown he is a swing-and-miss pitcher. He will get his share of strikeouts. In the game I watched, there wasn't even as much as a loud foul ball hit off Joseph's pitches. He has struck out all six hitters he's faced this spring. Five were left-handed hitters.

There are only two issues I feel could disrupt Joseph's career path to success.

First and foremost, Joseph will have to retain the good command I saw of both pitches. Because he extends himself so, I'm not sure he will be able to consistently repeat his delivery and keep his command. If Joseph's delivery gets out of sync, he will lose control and start walking people.

Joseph is appropriately aggressive in his approach. He comes right after hitters and wastes no time between pitches. Joseph is in total control on the mound. But he uses a whole lot of energy in his delivery. Joseph isn't violent, although he has a lot of movement in his body. He almost has his back to the hitter during his motion. That's acceptable as long as Joseph retains his focus and hits his spots, which he did when I saw him.

If Joseph could tame some of the excess, it may work to his benefit in clearing his hips and extending his arm pitch after pitch. So far, I've seen that ability. He just has to keep it up.

I have less concern with the second issue I think could surface.

I am concerned that in an effort to improve his velocity, Joseph may try to overthrow his fastball. That could cause the pitch to flatten out and lose the late life he now enjoys with his controlled velocity. It will take discipline for him to keep within his current abilities and success pattern. Joseph will be fine throwing it at high 80s to low 90s. I think he'll sit at an easy 93 mph when he settles in to his role.

In his Minor League career, Joseph has shown an ability to get hitters out under pressure. During the 2012 season, his best in professional baseball, Joseph threw 69 2/3 innings combined over two classifications. He pitched at Double-A Pensacola and Triple-A Louisville in the Reds organization and Triple-A Omaha for Kansas City. Joseph had a combined 2.33 ERA, 1.234 WHIP and 20 saves, and walked an average of 3.9 hitters per nine innings, with 11.2 strikeouts per nine. It would be good for him to reduce that walk rate.

Joseph is extremely difficult to hit because he changes both the balance and the eye level of the hitter. Using that two-seam sinking fastball to set up the slider, the hitter doesn't know which pitch is coming. Guessing one way or the other may make the hitter lose the entire trajectory of the pitch. If he ever perfects a changeup, hitters will have even less chance for success.

It's always difficult to lose a power arm like that of Broxton. However, the Royals have added two very effective pitchers with the acquisitions of Sulbaran and Joseph. MLB.com has ranked Joseph as the seventh-best Royals prospect.

From what I observed, Joseph is close to being ready to bring his power arm to the Royals' bullpen.

Bernie Pleskoff has served as a professional scout for the Houston Astros and Seattle Mariners. Follow @BerniePleskoff on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.